Internals in a helically coiled heat exchanger for suppressing gas vortices

ABSTRACT

The invention relates to a heat exchanger for indirect heat exchange between a first and second medium having: a shell, extending along a longitudinal axis and surrounding a shell space for receiving the first medium, and a plurality of tubes coiled helically onto a core tube which extends along the longitudinal axis in the shell space forming a tube bundle. The tube bundle comprises a number of tube layers lying one on top of the other in the radial direction. The second medium is conducted within the tubes to exchange heat indirectly with the first medium. The at least one distributor arm distributes a liquid phase of the first medium to an upper side of the tube bundle. The at least one distributor arm has, opposite from the upper side, a bottom with through-openings, so that the liquid phase can be passed to the upper side of the tube bundle. From an underside of the bottom of the at least one distributor arm, and at least one directing element projects in the direction of the upper side of the tube bundle and extends along the longitudinal axis toward the upper side of the tube bundle. The at least one directing element extends in a circumferential direction of the tube bundle over at least half the width of the bottom of the at least one distributor arm and/or the at least one directing element projects along the longitudinal axis into a gap of the tube bundle arranged between two tube layers of the tube bundle.

The invention relates to a helically coiled heat exchanger.

Such helically coiled heat exchangers are used in a wide variety of processes, for example in ethylene or natural gas plants (LNG plants for short).

In the case of such heat exchangers, the coolant in the shell space of the heat exchanger is usually applied to a bundle of tubes which is arranged in the shell space and comprises tubes which are helically coiled on a core tube and in which the process stream to be cooled is conducted. The coolant is in this case introduced into the heat exchanger in a two-phase state, the liquid phase being separated from the gaseous phase in a distributor and distributed to the bundle of tubes by way of distributor arms.

During the operation of the heat exchanger, gas vortices may occur in the shell space. If such vortices are in the upper portion of the heat exchanger, in the region of the upper side of the bundle of tubes, they may divert the liquid phase flowing out from the distributor arms in a direction transverse to the longitudinal axis of the shell or of the bundle of tubes, which has the consequence that the liquid phase can longer be applied to the bundle of tubes in an equally distributed manner. Such an uneven distribution of the liquid phase or the coolant reduces the effectiveness of the heat exchanger significantly.

Against this background, the present invention is therefore based on the object of providing a heat exchanger that is improved with regard to the aforementioned problem.

This object is achieved by a heat exchanger with the features of claim 1.

Advantageous configurations of the invention are provided in the corresponding subclaims and are described below.

According to claim 1, heat exchanger for indirect heat exchange between a first and a second medium is provided, having

-   -   a shell, which is made to extend along a longitudinal axis and         surrounds a shell space, which serves for receiving the first         medium,     -   a plurality of tubes, which are in each case coiled helically         onto a core tube of the heat exchanger, which extends along the         longitudinal axis in the shell space, so that the tubes form a         bundle of tubes of the heat exchanger which is arranged in the         shell space and comprises a number of tube layers lying one on         top of the other in the radial direction of the bundle of tubes,         the second medium being conducted in the bundle of tubes, so         that heat is exchangeable indirectly between the first medium         and the second medium, and     -   at least one distributor arm for distributing a liquid phase of         the first medium to an upper side of the bundle of tubes facing         the at least one distributor arm, the at least one distributor         arm having opposite from the upper side a bottom with         through-openings, so that the liquid phase can be passed to the         upper side of the bundle of tubes by way of the         through-openings.

It is then provided according to the invention that, from an underside of the bottom of the at least one distributor arm that is facing the upper side of the bundle of tubes, at least one directing element projects in the direction of the upper side of the bundle of tubes or extends along the longitudinal axis toward the upper side of the bundle of tubes, the at least one directing element extending in a circumferential direction of the bundle of tubes at least over half of a width of the bottom of the at least one distributor arm and/or the at least one directing element projecting along the longitudinal axis into a gap of the bundle of tubes between two tube layers of the bundle of tubes.

Said upper side of the bundle of tubes is formed by the uppermost tube portions of the tubes of the bundle of tubes that are coiled around the core tube and extends along a horizontal plane or along a plane that runs perpendicularly in relation to the longitudinal axis. However, said upper side does not have to run completely flat or parallel to this plane, but may have curvatures and a varying height profile (with respect to the longitudinal axis). The reason for this is in particular that the individual tubes or tube portions on said upper side of the bundle of tubes have a circular cross section. It is also provided in particular that, on said upper side, upper end portions of the tubes of the bundle of tubes are gathered into tube clusters, which project from the upper side and are led through gaps between distributor arms that are neighboring in the circumferential direction. The tube clusters in this case end in each case in a tubesheet, in which the individual tubes are anchored, the respective tubesheet being fixed on the cylindrical shell of the heat exchanger. The upper side of the bundle of tubes also deviates from a horizontal path due to the tube clusters that are led away from the bundle of tubes. The tubes of the bundle of tubes may in particular be coiled onto the core tube or fixed thereon in such a way that the core tube can bear the load of the bundle of tubes. As an alternative to this, the weight of the bundle may be borne by so-called bearing webs, which are arranged between the tube layers and are connected to them. The bearing webs may in this case project beyond the upper side of the bundle of tubes and may be welded on or fixed there on bearing arms. The bearing arms may in particular be fixed both on the core tube and on the shell; they consequently connect the core tube and the shell above the bundle of tubes in the form of spokes. In the case of this variant, the bearing arms ultimately bear the bundle of tubes and the core tube by way of the shell. This upper part in the heat exchanger forms the so-called fixed bearing, since the shell and the core tube are fixedly connected to one another here, while at the bottom of the heat exchanger the core tube is connected to the shell in particular by way of a sliding bearing.

The fact that the at least one directing element projects in the direction of the upper side of the bundle of tubes or extends toward the upper side of the bundle of tubes may mean in particular that the at least one directing element ends before or at the upper side of the bundle of tubes, there preferably being a clearance between the directing device and the upper side, or specifically enough clearance to avoid mechanical contact with the bundle of tubes, in order to protect the bundle of tubes from leakages.

It may also be provided that the at least one directing element projects into the bundle of tubes along the longitudinal axis, in particular into a gap (or a number of gaps) between two tube layers of the bundle of tubes. These tube layers may be for example tube layers of the bundle of tubes that are neighboring in the radial direction. In this case, the at least one directing element may project into the bundle of tubes only by a certain portion or over its entire length in a plane running perpendicular to the longitudinal axis. A suitable gap into which the at least one directing element can project may also be present between two tube layers that are not directly neighboring in the radial direction. Thus, because of the tubes being led out into the clusters, the tube layers end at different heights along the longitudinal axis of the shell (these differences may be for example 100 mm to 150 mm). Thus, for example at a specific location along the circumference, the nth tube layer may end high, but the (n+1)th tube layer low, and the (n+2)th tube layer high again. These gaps between every second layer (here above the (n+1)th tube layer) may also be used.

In the embodiments described herein, in particular concerning those embodiments in which the respective directing element is not formed as a tube, it may be provided that the respective directing element does not extend in the axial direction, i.e. along the longitudinal axis, downward as far as the upper side of the bundle of tubes or beyond (for example into a gap of the bundle of tubes), but ends above the upper side. The respective directing element may in this case extend over at least 70%, in particular at least 80%, in particular at least 90%, in particular at least 95% or in particular at least 99%, of the vertical distance between the upper side of the bundle of tubes and the underside of the bottom of the respective distributor arm.

In all of the embodiments, the at least one directing element is preferably formed separately from the core tube, i.e. in other words the core tube is not understood as meaning a directing element projecting from the bottom of the at least one distributor arm.

The at least one directing element is formed so as to prevent a cross flow of the gaseous and/or liquid phase of the first medium on the upper side of the bundle of tubes (for example because of gas vortices), or performs this function because of its arrangement with respect to the upper side of the bundle of tubes. Understood here as a cross flow is in particular a flow that takes place in a direction which runs along the upper side of the bundle of tubes or the direction of which has at least one component that runs perpendicularly to the longitudinal axis.

The directing element may in this case either shield the liquid phase from gas vortices, in particular cross flows on the upper side of the bundle of tubes, or by its arrangement between the bottom of the at least one distributor arm and the upper side of the bundle of tubes, suppress or at least reduce such cross flows, so that the liquid phase can be distributed directly in the downward direction by following gravitational force.

According to a particularly preferred embodiment of the invention, it is provided that the at least one directing element is formed as a directing plate, in particular a baffle plate, which is connected in particular by way of an upper peripheral region to the bottom of the at least one distributor arm, an opposite lower periphery extending, as described above, at least down as far as the upper side of the bundle of tubes. The at least one directing element or the directing plate is preferably disposed perpendicularly on the underside of the bottom of the at least one distributor arm. The directing plate forms in particular a closed surface area without apertures/holes.

It is also provided according to one embodiment of the invention that the at least one directing element extends along a circumferential direction of the bundle of tubes and also in particular along the longitudinal axis of the shell.

It is also provided according to one embodiment of the invention that the at least one distributor arm has two side walls, which lie opposite one another in the circumferential direction of the bundle of tubes or the shell, extend in each case along the radial direction of the bundle of tubes from the inside to the outside toward the shell of the heat exchanger and also in each case along the longitudinal axis from the bottom upward to a roof of the at least one distributor arm.

It is also provided according to one embodiment of the invention that the at least one directing element extends in the circumferential direction of the shell or the bundle of tubes from one side wall to the other side wall. This means in other words that the directing element extends in the circumferential direction over an entire width of the bottom of the respective distributor arm.

It is also provided according to one embodiment of the invention that the at least one directing element has in a plane running perpendicularly to the longitudinal axis a curvature, in particular a curvature with a constant radius of curvature, so that in particular an inner side of the directing element that is facing the core tube is at a constant distance overall from the longitudinal axis. In this embodiment, the at least one directing element therefore has at least a concavely curved inner side, which is facing the core tube, and an outer side, facing away from the core tube or the inner side, that has a convex curvature.

Furthermore, said radius of curvature of the at least one or the respective directing element may lie between the radius of curvature of the tubes of a tube layer lying further inward in the radial direction and the radius of curvature of the tubes of a tube layer lying further outward in the radial direction.

It is also provided according to one embodiment of the invention that the heat exchanger has a number of directing elements, which project in each case from the underside of the bottom of the at least one distributor arm that is facing the upper side of the bundle of tubes in the direction of the upper side of the bundle of tubes or extend along the longitudinal axis toward the upper side of the bundle of tubes (also see above), the directing elements extending in each case in a circumferential direction of the bundle of tubes at least over half of the width of the bottom of the at least one distributor arm and/or the directing elements projecting in each case along the longitudinal axis into a gap of the bundle of tubes between two tube layers of the bundle of tubes.

These multiple directing elements may be in particular a number of the (in particular curved) directing plates described above, which may in each case be disposed in particular with a lower periphery in gaps between neighboring tube layers.

The heat exchanger may of course also have a plurality of distributor arms, which extend in each case in a radial direction from the core tube toward the shell, there being between every two distributor arms that are neighboring in the circumferential direction of the shell an intermediate space through which tubes, or in each case a tube cluster, of the bundle of tubes are led past the distributor arms to an assigned tubesheet, which is fixed on the shell. In principle, at least one or more directing elements according to the invention may be provided on all of the distributor arms.

The at least one distributor arm or the respective distributor arm may have—with respect to a horizontal plane or plane made to extend perpendicularly to the longitudinal axis—a cross section in the form of a sector of a circle, i.e. like a piece of pie. Correspondingly, the respective bottom of a distributor arm is preferably formed correspondingly in the form of a sector of a circle.

If a number of directing elements, in particular directing plates (see above), are provided, it is preferably provided that the directing elements are arranged next to one another in a radial direction along which the at least one distributor arm extends from the core tube toward the shell. In particular, in this case all of the directing plates may extend along the circumferential direction of the shell, in particular along the underside of the bottom from one side wall to the other side wall of the distributor arm concerned. The individual directing elements or directing plates may in this case project in each case into a gap between neighboring tube layers of the bundle of tubes.

The directing plates that are situated further inward in the radial direction, i.e. situated closer to the core tube, may have a smaller length in the circumferential direction of the shell than the peripheral plates situated further outward, for example if the respective distributor arm has a cross-sectional form of a sector of a circle (see above) and the respective directing plate extends from one side wall of the distributor arm concerned to the other side wall of the distributor arm.

In an alternative embodiment, the at least one directing element or the number of directing elements is or are formed in each case as a tube that is in flow connection with an assigned through-opening of the bottom. The respective tube may in this case adjoin an assigned through-opening of the bottom of the respective distributor arm. In particular, each through-opening of the respective distributor arm may be connected to such a tube in the way described above. It is also conceivable that a number of tubes are provided as directing elements, a number of through-openings opening out into the same tube, which then has a correspondingly greater diameter.

In this case, the tubes do not necessarily have to have a circular cross section. Rather, here the directing elements may also be formed in each case by a channel that extends in the direction of the longitudinal axis, with a wall running around, the channel being in flow connection with at least one through-opening of the bottom.

According to a further alternative embodiment, it is provided that the at least one directing element forms a plurality of channels that extend in the direction of the longitudinal axis and have respective walls, neighboring channels forming common walls or the walls of neighboring channels being adjacent to one another, the respective wall bounding a region of the shell space between the bottom of the at least one distributor arm and the upper side of the bundle of tubes into which at least one through-opening of the bottom of the at least one distributor arm opens out.

It is in this case provided according to one embodiment that the channels are formed in cross section in an n-gonal manner, n being greater than or equal to 3, in particular 4 or 6. The channels may therefore be formed in particular in a rectangular (n=4) or honeycomb (n=6) manner in cross section. It may also be provided according to one embodiment of the invention that the at least one directing element is formed by a wall which extends along a periphery of the bottom and surrounds a region of the shell space between the bottom of the at least one distributor arm and the upper side of the bundle of tubes into which the through-opening of the bottom of the at least one distributor arm opens out. The wall may extend in particular from the core tube along said periphery in the radial direction as far as the end-face wall of the distributor arm, from there in the circumferential direction of the shell to the opposite side wall of the distributor arm and from there along the radial direction back to the core tube.

In other words, in the case of this embodiment, in particular a channel that is made to extend in the direction of the longitudinal axis is therefore bounded by the wall, it being possible for the wall to form a continuation of the side walls of the distributor arm in the direction of the longitudinal axis, projecting from the bottom of the distributor arm.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and advantages of the invention are to be explained by the following description of the figures of an exemplary embodiment by reference to the figures, in which:

FIG. 1 shows a schematic sectional representation of a heat exchanger according to the invention with directing elements in the form of directing plates, which project from an underside of the bottom of a distributor arm of the heat exchanger;

FIG. 2 shows a schematic plan view of the underside of the bottom of the heat exchanger shown in FIG. 1;

FIG. 3 shows a perspective, partially sectional view of the heat exchanger according to the invention of the type from FIGS. 1 and 2;

FIG. 4 shows a schematic plan view of the underside of a bottom of a heat exchanger according to the invention from which a honeycomb-shaped directing element projects;

FIG. 5 shows a schematic plan view of the underside of a bottom of a heat exchanger according to the invention from which a directing element with rectangular cells projects;

FIG. 6 shows a schematic plan view of the underside of a bottom of a heat exchanger according to the invention from which a directing element with a wall running along the bottom projects;

FIG. 7 shows a schematic sectional view of the heat exchanger shown in FIG. 6;

FIG. 8 shows a schematic plan view of the underside of a bottom of a heat exchanger according to the invention from which tubular directing elements project; and

FIG. 9 shows a schematic sectional view of the heat exchanger shown in FIG. 8.

FIG. 1 shows in conjunction with FIGS. 2 and 3 an embodiment of a heat exchanger according to the invention for indirect heat exchange between a first and a second medium M, M′. The heat exchanger 1 has a shell 5, which is made to extend along a longitudinal axis z and surrounds a shell space 6, which serves for receiving the first medium M, and also a plurality of tubes 30, which are in each case coiled helically onto a core tube 300 of the heat exchanger 1, which extends along the longitudinal axis z in the shell space 6, so that the tubes 30 form a bundle of tubes 3 of the heat exchanger 1 which is arranged in the shell space 6 and comprises a number of tube layers 32 lying one on top of the other in the radial direction R of the bundle of tubes 3, the second medium M′ being conducted in the bundle of tubes 3, so that heat is exchangeable indirectly between the first medium M and the second medium M′. The second medium M′ can be introduced into the bundle of tubes 3 in particular through at least one nozzle provided on the shell 5 (not shown in FIG. 3) and can be drawn off from the bundle of tubes 3 by way of at least one nozzle 4 provided on the shell 5. The bundle of tubes 3 may also be surrounded by a jacket 7, which serves for reducing a bypass flow in the shell space 6 (past the bundle of tubes 3).

The heat exchanger 1 also has at least one distributor arm 21, preferably a number of distributor arms 21, which serve(s) for distributing a liquid phase F of the first medium M to an upper side 3 a of the bundle of tubes 3 facing the respective distributor arm 21, the respective distributor arm 21 having opposite from the upper side 3 a a bottom 200 with through-openings 205, so that the liquid phase F can be passed to the upper side 3 a of the bundle of tubes 3 by way of the through-openings 205. As a difference from FIG. 3, for the sake of simplicity FIGS. 2, 4, 5, 6 and 8 only show one distributor arm 21 in each case.

The respective distributor arm 21 projects in particular in a radial direction R, which is disposed perpendicularly on the longitudinal axis z, from the core tube 300 and is preferably in flow connection with it. The core tube 300 in turn projects from a pre-distributor 20, which is arranged above the bundle of tubes 3 and the distributor arms 21 and in which the first medium M is collected and in particular degassed. The liquid phase F can correspondingly flow from the pre-distributor 20 into the core tube 300 and subsequently into the respective distributor arm 21. Instead of the core tube 100, the liquid phase F may also be fed into the respective distributor arm 21 by way of an annular channel, which for example runs around the inside of the shell 5. Then, from an underside 200 a of the bottom 200 of the respective distributor arm 21 that is facing the upper side 3 a of the bundle of tubes 3, at least one directing element 22 projects in the direction of the upper side 3 a of the bundle of tubes 3 and thereby extends in each case along the longitudinal axis z toward the upper side 3 a of the bundle of tubes 3. Preferably, the at least one directing element 22 extends in a circumferential direction U of the bundle of tubes 3 at least over half of the width B of the bottom 200 of the at least one distributor arm 21 (cf. FIG. 2).

According to the embodiment shown in FIGS. 1 to 3, a number of such directing elements 22 are provided, formed in each case as a directing plate. The respective directing plate 22 is in this case connected by way of an upper peripheral region 221—with respect to the vertically aligned longitudinal axis z—to the underside 200 a of the bottom 200 of the respective distributor arm 22, an opposite lower peripheral region 222 of the respective directing plate 22 ending at the upper side 3 a of the bundle of tubes 3 or,as shown in FIG. 1, in each case projecting into a gap 31 between two tube layers 32 lying one on top of the other in the radial direction R. As already mentioned above, this may be a gap 31 between neighboring tube layers 32 or some other depression/gap between two tube layers 32, for example a gap above a tube layer which lies at a lower level in comparison with the two tube layers adjacent on both sides, therefore represents a gap. Preferably, mechanical contact between the respective directing element 22 and the bundle of tubes 3 is avoided, in order to reduce the risk of leakage of the bundle of tubes 3.

The directing elements or plates 22 are preferably arranged next to one another in the radial direction R, along which the respective distributor arm 21 extends from the core tube 300 toward the shell 5, one or more of the through-openings 205 in each case opening out into an intermediate space between two directing plates 22 that are neighboring in the radial direction R, so that the liquid phase F can be discharged into the respective intermediate space above the upper side 3 a of the bundle of tubes 3.

The directing elements 22 configured in such a way serve in this case for preventing a cross flow of the gaseous phase G of the first medium M on or along the upper side 3 a of the bundle of tubes 3 or along the radial direction R. As a result, the liquid phase F can be discharged undisturbed by way of the distributor arms 21 along the longitudinal axis z in the downward direction, and an uneven distribution of the liquid phase F is prevented.

As can be seen from FIGS. 1 to 3, the respective directing plate 22 preferably extends along a circumferential direction U of the bundle of tubes 3 or the shell 5 and in this case preferably has a curved path (in particular with a radius of curvature R′), so that a concavely curved side of the respective directing plate 22 is facing the core tube 300, whereas the respective convexly curved side is facing the shell 5 in the outward direction.

The respective distributor 21 has furthermore two side walls 203, 204, which lie opposite one another in the circumferential direction U of the bundle of tubes 3 or the shell 5, extend in each case along the radial direction R of the bundle of tubes 3 from the inside to the outside toward the shell 5 of the heat exchanger 1 and in each case project upward along the longitudinal axis z from a periphery 200 b of the bottom 200 of the respective distributor arm 21.

The respective distributor arm 21 has furthermore an end-face wall 201, which lies opposite the shell 5 in the radial direction R and connects the two side walls 203, 204 to one another. In the upward direction, the respective distributor arm 21 is preferably closed by a roof 206, which is connected to the respective side walls 203, 204 and the end-face wall 201 and slopes up toward the core tube 300, so that the gaseous phase G of the first medium M can rise up along the ridge 206 to the core tube 300.

It is preferably also provided (cf. in particular FIG. 2) that the respective directing element 22 extends on the underside 200 a of the bottom 200 of the respective distributor arm 21 in the circumferential direction U from the one side wall 203 to the other side wall 204 (that is to say over an entire width B of the bottom 200 in the circumferential direction U, it being possible for the width B of the bottom 200 to vary in the radial direction R, in particular in the case of a bottom 200 in the form of a sector of a circle).

Between every two distributor arms 21 that are neighboring in the circumferential direction U of the shell 5 there is a gap through which a tube cluster 33 of the bundle of tubes 3, formed by end portions of the tubes 3, is in each case led past the distributor arms 21 to an assigned tubesheet 34, which in each case is fixed on the shell 5.

FIG. 4 shows a further embodiment of the present invention, in which a contiguous directing element 22 in each case extends from the underside 200 a of the bottom 200 of the respective distributor arm 21 in the direction of the upper side 3 a of the bundle of tubes 3. The respective directing element 22 forms a plurality of channels 22 a, which in each case extend along the longitudinal axis z, the respective channel 22 a being surrounded by a running-around wall 22 b and in each case bounding a region B′ of the shell space 6 between the bottom 200 of the at least one distributor arm 21 and the upper side 3 a of the bundle of tubes 3 into which at least one through-opening 205 of the bottom 200 of the at least one distributor 21 opens out.

The individual running-around walls 22 b are formed in particular hexagonally in cross section (with respect to a cross-sectional plane made to extend parallel to the respective bottom 200) and are connected in each case to neighboring walls 22 b, so that the respective directing element 22 forms overall a honeycomb structure, as can be seen from FIG. 4. The individual channels 22 a therefore share their respective running-around wall 22 b with the neighboring channels 22 a.

FIG. 5 shows a modification of the directing element 22 shown in FIG. 4, here, as a difference from FIG. 4, the individual channels 22 a having a rectangular shape with respect to the cross-sectional plane defined above. In FIGS. 4 and 5, the channels 22 a may deviate from the hexagonal or rectangular shaping at the periphery 200 b of the underside 200 a of the respective bottom 200 (in particular because of the configuration of the bottoms 200 of the distributor arms 21 preferably in the form of sectors of a circle).

FIG. 6 shows in conjunction with FIG. 7 a further embodiment of a directing element 22 according to the invention, in which the at least one directing element 22 is formed by a wall 22, which extends along an outer periphery 200 b of the bottom 200 and projects from the underside 200 a of the bottom 200 of the assigned distributor arm 21 in the direction of the upper side 3 a of the bundle of tubes 3. The wall or the directing element 22 has here a first portion 22 c, which extends in the radial direction R from the core tube 300 outward to the end-face wall 201 of the assigned distributor arm 21. From there, a second portion 22 d of the wall 22 that is connected to the first portion 22 c of the wall 22 extends in the circumferential direction U to the opposite portion of the periphery 200 b of the bottom 200 and is connected there to a third portion 22 e of the wall 22, the third portion 22 e of the wall 22 extending along the radial direction R back to the core tube 300. The directing element 22 consequently surrounds a region B′ of the shell space 6 between the bottom 200 of the assigned distributor and 21 and the upper side 3 a of the bundle of tubes 3 into which the through-opening 205 of the bottom 200 of the respective distributor arm 21 opens out. In this case, the individual portions 22 c, 22 d, 22 e of the wall 22 in particular are connected by way of an upper peripheral region 221 to the underside 200 a of the respective bottom 200, whereas the respectively opposite lower peripheral region 222 runs along the upper side 3 a of the bundle of tubes 3. In this case, the respectively opposite lower peripheral region 222 may also project by a certain portion into one or more gaps of the tube bundle 3.

According to a further embodiment, shown in FIGS. 8 and 9, it is provided that the respective distributor arm 21 has a number of directing elements 22, which are configured here in each case as a channel 22 with a running-around wall 220, it being possible for the respective channel 22 to be formed by a tube 22 with in particular a circular cross section, the respective tube 22 or the respective channel 22 projecting from the underside 200 a of the bottom 200 of the respective distributor arm 21. In this case, the through-openings 205 of the bottom 200 of the respective distributor arm 21 open out in each case into one of the tubes 22. The tubes 22 extend in each case along the longitudinal axis z downward to the upper side 3 a of the bundle of tubes 3 and end at the upper side 3 a or project in each case with one end into a gap of the tube bundle 3, for example a gap 31 that is present between two tube layers 32.

List of reference numerals  1 Heat exchanger or latent heat exchanger  3 Bundle of tubes  3a Upper side  4 Nozzle  5 Shell  6 Shell space  7 Jacket 10 Web 20 Pre-distributor 22 Directing elements, wall 22a Channel 22b Wall 22c, 22d, 22e Portion 30 Tubes 31 Gap 32 Tube layer 33 Tube cluster 34 Tubesheet 200  Bottom 200a  Underside 200b  Periphery 201  End-face wall 203, 204 Side wall 205  Through-opening 206  Roof 220  Wall 221  Upper peripheral region 222  Lower peripheral region 300  Core tube M First medium M′ Second medium R Radial direction U Circumferential direction z Longitudinal axis B Width B′ Region R′ Radius of curvature 

1. Heat exchanger (1) for indirect heat exchange between a first and a second medium (M, M′), having: a shell (5), which is made to extend along a longitudinal axis (z) and surrounds a shell space (6), which serves for receiving the first medium (M), a plurality of tubes (30), which are in each case coiled helically onto a core tube (300) of the heat exchanger (1), which extends along the longitudinal axis (z) in the shell space (6), so that the tubes (30) form a bundle of tubes (3) of the heat exchanger (1) which is arranged in the shell space and comprises a number of tube layers (4) lying one on top of the other in the radial direction (R) of the bundle of tubes (3), the second medium (M′) being able to be conducted through at least one tube (30) of the bundle of tubes (3), so that heat is exchangeable indirectly between the first medium (M) and the second medium (M′), and at least one distributor arm (21) for distributing a liquid phase (F) of the first medium (M) to an upper side (3 a) of the bundle of tubes (3) facing the at least one distributor arm (21), the at least one distributor arm (21) having opposite from the upper side (3 a) a bottom (200) with through-openings (205), so that the liquid phase (F) can be passed to the upper side (3 a) of the bundle of tubes (3) by way of the through-openings (205), characterized in that, from an underside (200 a) of the bottom (200) of the at least one distributor arm (21) that is facing the upper side (3 a) of the bundle of tubes (3), at least one directing element (22) projects in the direction of the upper side (3 a) of the bundle of tubes (3), the at least one directing element (22) extending in a circumferential direction (U) of the bundle of tubes (3) at least over half of the respective width (B) of the bottom (200) of the at least one distributor arm (21) and/or the at least one directing element (22) projecting along the longitudinal axis (z) into a gap (31) of the bundle of tubes (3) that is arranged between two tube layers (32) of the bundle of tubes (3).
 2. Heat exchanger according to claim 1, characterized in that the at least one directing element (22) is formed so as to prevent a cross flow of the gaseous and/or liquid phase (F) of the first medium (M) on the upper side (3 a) of the bundle of tubes (3).
 3. Heat exchanger according to claim 1, characterized in that the at least one directing element (22) is formed as a directing plate (22).
 4. Heat exchanger according to claim 1, characterized in that the at least one directing element (22) extends along the circumferential direction (U) of the bundle of tubes.
 5. Heat exchanger according to claim 1, characterized in that the at least one distributor arm (21) has two side walls (203, 204), which lie opposite one another in the circumferential direction (U) of the bundle of tubes (3), extend in each case along the radial direction (R) of the bundle of tubes (3), the at least one directing element (22) extending in the circumferential direction (U) of the shell (5) from one side wall (203) to the other side wall (204).
 6. Heat exchanger according to claim 1, characterized in that the at least one directing element (22) has in a plane running perpendicularly to the longitudinal axis (z) a curvature, in particular a curvature with a constant radius of curvature (R′).
 7. Heat exchanger according to claim 1, characterized in that the heat exchanger (1) has a number of directing elements (22), which project in each case from an underside (200 a) of the bottom (200) of the at least one distributor arm (21) that is facing the upper side (3 a) of the bundle of tubes (3) in the direction of the upper side (3 a) of the bundle of tubes (3), the directing elements (22) in each case extending in a circumferential direction (U) of the bundle of tubes (3) at least over half of the respective width (B) of the bottom (200) of the at least one distributor arm (21) and/or the at least one directing element (22) in each case projecting along the longitudinal axis (z) into a gap (31) of the bundle of tubes (3) that is arranged between two tube layers (32) of the bundle of tubes (3).
 8. Heat exchanger according to claim 1, characterized in that the directing elements (22) are arranged next to one another in a radial direction (R), along which the at least one distributor arm (21) extends from the core tube (300) toward the shell (5).
 9. Heat exchanger according to claim 1, characterized in that the at least one directing element (22) forms a channel (22) that extends in the direction of the longitudinal axis (z), with a wall (220), the channel (22) being in flow connection with at least one through-opening (205) of the bottom (200).
 10. Heat exchanger according to claim 9, characterized in that the channel (22) is formed by a tube (22) with in particular a circular cross section.
 11. Heat exchanger according to claim 1, characterized in that the at least one directing element (22) forms a plurality of channels (22 a) that extend in the direction of the longitudinal axis (z) and have respective walls (22 b), neighboring channels (22 a) forming common walls (22 b) or the walls (22 b) of neighboring channels (22 a) being adjacent to one another, the respective wall (22 b) bounding a region (B′) of the shell space (6) between the bottom (200) of the at least one distributor arm (21) and the upper side (3 a) of the bundle of tubes (3) into which at least one through-opening (205) of the bottom (200) of the at least one distributor arm (21) opens out.
 12. Heat exchanger according to claim 11, characterized in that the channels (22 a) are formed in cross section in an n-gonal manner, n being greater than or equal to 3, and in particular n being equal to 4 or equal to
 6. 13. Heat exchanger according to claim 1, characterized in that the at least one directing element (22) is formed by a wall (22) which extends along a periphery (200 b) of the bottom (200) and surrounds a region (B′) of the shell space (6) between the bottom (200) of the at least one distributor arm (21) and the upper side (3 a) of the bundle of tubes (3) into which the through-openings (205) of the bottom (200) of the at least one distributor arm (21) open out. 